锌对铅致大鼠心肌氧化性损伤的保护作用

Study on protective effects of zinc on myocardial microsome membra ne oxidant injury in rats exposed to low level of lead

目的 探讨硫酸锌 (ZnSO4)对低水平醋酸铅 (PbAc2 )暴露的雄性SD大鼠心肌微粒体膜 (MMS)氧化性损伤保护作用的可能机制。方法 暴露组 :PbAc2 3 0mg (kg·d) ;干预组 (3个 ) :剂量为PbAc2 3 0mg (kg·d)分别 +ZnSO42 5、5、1 0mg(kg·d) ;对照组 :给等容积蒸馏水。连续灌胃 9周后断头取血分析铅、血锌含量 ;取尿液分析尿铅含量 ;取心肌制备其MMS分析Na+,K+ ATP酶 (Na泵 )、Ca2 + ATP酶 (Ca泵 )、超氧化物歧化酶 (SOD)活力、丙二醛 (MDA)含量。离体实验将大鼠MMS悬液与最终浓度PbAc2 0 4mmol L组成混合液 ,把此混合液分为 4组 ,其中 3组分别加ZnSO40 3、0 6、1 2mmol L ,37℃共同温育 30min后 ,观察ZnSO4对PbAc2 致MMS氧化性损伤的保护作用。结果 在体实验 3个染PbAc2 +ZnSO4干预组血铅平均值分别为 0 1 7、0 1 6、0 1 5μmol L;MMSMDA含量平均值分别为 2 2 8、2 1 7、2 0 7μmol g;Ca泵活性平均值分别为 1 3 1 7、1 2 98、1 2 52mmol (h.g) ,均明显低于染PbAc2 3 0mg (kg·d)组 (P <0 0 5或P <0 0 1 ) ;而 3个染PbAc2 +ZnSO4干预组血锌、尿铅含量、MMSNa泵和SOD活力平均值分别为 72、78、88μmol L ,0 33、0 36、0 39μmol L ,1 0 0 5、1 1 39、1 1 95mmol (h .g) ;1 3、1 4。

Objective The possible mechanisms of protective e ffects of zinc sulfate(ZnSO 4) on myocardial microsome membrane(MMS) oxidant injury from low level lead exposure were investigated.Methods Male SD rats were treated orally with 30 mg/kg lead ace tatic(PbAc 2) group,and given orally with 30 mg/kg PbAc 2+2 5,5,10 mg/kg ZnSO 4 groups separately,and normal control group for 9 weeks.The pro tective effects \%in vitro\% by incubation at 37℃ for 30 min of MMS exposed PbA c 2(0\^4 mmol/L)+separately given ZnSO 4(0\^3,0\^6,1\2 mmol/L) were observed.Results Blood lead concentrations(0\^17,0\^16,0\^15 μmol/L),M MS Ca 2+ -ATPase(Ca pump)activities (13\17,12\98,12 52 mmol/(h.g)) and m alondialdehyde(MDA) concentrations(2\28,2\17,2\07 μmol/g)of PbAc 2(30 mg/ kg)+ ZnSO 4(2\5,5,10 mg/kg)gavage groups were all significantly lower than th ose of PbAc 2(30 mg/kg) gavage SD rats(P<0 01).And leves of blood z in(72,78,88 μmol/L),urinary lead contents(0\^33,0\^36,0\^39 μmol/L),MMS Na\+ +,K\++-A TPase(Na pump) activities(10\^05,11 39,11 95 mmol/(h.g)) and superoxide dism utase (SOD) activities (1\3,1\4,1\3 μmol/(min.g))of PbAc 2(30 mg/kg )+Zn SO 4(2 \^5,5,10 mg/kg)gavage groups separately were all significantly higher than those of the PbAc 2(30 mg/kg)gavage group(P<0 05 or P<0 01).The in v itro and in vivo tests showed the same results except the increase of decl ine Ca 2+ -ATPase activities indused by PbAc 2 \%in vitro\%.Conclusion These results suggest that the possible mechanisms of protective effect of ZnSO 4 on MMS Na pump activities and anti-lipoperoxidati o n reduction from low level lead exposure are decrease on lead and MMS MDA accumu lation,and increase in blood zince levels,SOD and Na pump activities of MMS.